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5. Connect water line and pressure relief drain line

a.  

Attach the HOT water supply line 
to the ¾" threaded connection on 
the HOT WATER VALVE using 
thread sealant on the threads 
of the water fitting. On US (union 
sweat) models, detach the copper 
tailpiece from the union assembly 
and sweat to the hot water supply 
line. Be sure to remove the 
O-ring from the tailpiece before 
seating. Allow tailpiece to cool before
reassembly to avoid damaging O-ring.

b.  

Attach the COLD water supply line to the ¾" threaded con-
nection on the COLD WATER VALVE using thread sealant on 
the threads of the water fitting. On US (union sweat) models, 
detach the copper tailpiece from the union assembly and 
sweat to the cold water supply line. Be sure to remove the 
O-ring from the tailpiece before seating.  Allow tailpiece to 
cool before reassembly to avoid damaging the O-ring.

c.  

Attach the drain line to the pressure relief valve and run line 
per local code requirements. 

6.  

Start-up & Normal Operation

a.  

Before turning on the supply water to the heater, make sure 
that the main valve handles on both the hot & cold valves are 
closed (Tee handle perpendicular to the main valve bodies). 
Also ensure that the purge port valve caps are tightened down 
and that the valves are in the closed position (Tee handle per-
pendicular to the purge port valve body). NEVER RELY ON 
THE PURGE CAP TO STOP THE WATER FLOW.

b.  

For water heater start-up, refer to the water heater owners’ 
manual.

c.  

During normal operation, the main water valves are open 
when the main valve handle is parallel with the main valve 
body and closed when the main valve handle is perpendicular 
to the main valve body. 

d.  

For the purge port valves, the purge port valve is open when 
the slot is parallel with the purge port valve body and closed 
when the slot is perpendicular to the purge port valve. 

7. Inspection and Maintenance

a.  

See tag attached to pressure relief valve for details.

WARNING: Hot water may be present in the system, use 
extreme caution when servicing tankless water heater. 
Hot water can cause personal injury, death and/or 
property damage.

8. Drain/Flush Operation

Note: The following are suggested instructions for the use of 
the service valves during draining and flushing of the tank-
less water heater. Please refer to the water heater owner’s 
manual for specific instructions.

a.  

Disconnect the power supply to the water heater.

b.  

Close the main water valve handles on the cold water valve 
(blue handle) and the hot water valve (red handle) by rotat-
ing each until they are perpendicular with the respective valve 
body. This shuts off the incoming cold water to the water 
heater and isolates the water heater from the hot water piping 
within the rest of the home.

c.  

The purge valve on the cold water valve (blue) is used as the 
flushing inlet and the purge valve on the hot water valve (red) 
is used for the flushing outlet or drain. Ensure that the purge 
port is closed (Tee handle perpendicular to the purge port 
valve body) before removing the purge port valve cap. 

d.  

Slowly open the drain caps on each purge port valve. Ensure 
that the rubber washer stays in the cap.

e.  

Continue with the manufacturer’s recommendations for 
attachment of the lines and for specific draining and flush-
ing instructions. To open the purge port valves, the slots are 
rotated so that they are parallel to the purge port valve body.

f.  

When flushing is complete and before the lines are removed, 
ensure that the purge port valves are closed. Remove the 
lines and reinstall the purge port valve caps, ensuring that the 
rubber washer is in the cap, and tighten.

Fig.5

Drain Line

Attach this end 
to tankless 
water heater

IS-TWH-UT_UTS  0849

EDP# 1915990

© Watts, 2008

USA:

  815 Chestnut St., No. Andover, MA 01845-6098; www.watts.com

Canada:

  5435 North Service Rd., Burlington, ONT. L7L 5H7; www.wattscanada.ca

W a t e r   S a f e t y   &   F l o w   C o n t r o l   P r o d u c t s

Limited Warranty:

 Watts Regulator Co. (the “Company”) warrants each product to be free from defects in material and workmanship under normal usage for a period of one year from the date of 

original shipment.  In the event of such defects within the warranty period, the Company will, at its option, replace or recondition the product without charge.  

THE WARRANTY SET FORTH HEREIN IS GIVEN EXPRESSLY AND IS THE ONLY WARRANTY GIVEN BY THE COMPANY WITH RESPECT TO THE PRODUCT.  THE COMPANY MAKES NO OTHER 
WARRANTIES, EXPRESS OR IMPLIED.  THE COMPANY HEREBY SPECIFICALLY DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED 
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

The remedy described in the first paragraph of this warranty shall constitute the sole and exclusive remedy for breach of warranty, and the Company shall not be responsible for any incidental, special 
or consequential damages, including without limitation, lost profits or the cost of repairing or replacing other property which is damaged if this product does not work properly, other costs resulting 
from labor charges, delays, vandalism, negligence, fouling caused by foreign material, damage from adverse water conditions, chemical, or any other circumstances over which the Company has no 
control.  This warranty shall be invalidated by any abuse, misuse, misapplication, improper installation or improper maintenance or alteration of the product.  
Some States do not allow limitations on how long an implied warranty lasts, and some States do not allow the exclusion or limitation of incidental or consequential damages.  Therefore the above 
limitations may not apply to you.  This Limited Warranty gives you specific legal rights, and you may have other rights that vary from State to State.  You should consult applicable state laws to 
determine your rights.  

SO FAR AS IS CONSISTENT WITH APPLICABLE STATE LAW, ANY IMPLIED WARRANTIES THAT MAY NOT BE DISCLAIMED, INCLUDING THE IMPLIED WARRANTIES OF 

MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE LIMITED IN DURATION TO ONE YEAR FROM THE DATE OF ORIGINAL SHIPMENT.

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